One day, many years ago, I was working in my college bookstore when this guy walks in wearing a T-shirt. “White Power,” it said.

I was chatting with a friend, Cathy Duncan, and what happened next was as smooth as if we had rehearsed it. All at once, she’s sitting on my lap or I’m sitting on hers — I can’t remember which — and that white girl gives this black guy a peck on the lips. In a loud voice she asks, “So, what time should I expect you home for dinner, honey?”

Mr. White Power glares malice and retreats. Cathy and I fall over laughing.

Which tells you something about how those of us who came of age in the first post- civil rights generation tended to view racism. We saw it as something we could dissipate with a laugh, a tired old thing that had bedeviled our parents, yes, but which we were beyond. We thought racism was over.

I’ve spent much of my life since then being disabused of that naiveté. Watching media empires built upon appeals to racial resentment, seeing the injustice system wield mass incarceration as a weapon against black men, bearing witness as the first African-American president produced his long form birth certificate, all helped me understand just how silly we were to believe bigotry was done.

So a chill crawled my spine last week as the Supreme Court heard arguments in a case that could result in gutting the Voting Rights Act. That landmark 1965 legislation gave the ballot to black voters who had previously been denied it by discriminatory laws, economic threats, violence and by registrars who challenged them with nonsense questions like, “How many bubbles are in a bar of soap.”

One of the act’s key provisions covers nine mostly Southern states and scores of municipalities with histories of such behavior. They must get federal approval before changing their voting procedures. The requirement may be stigmatizing; but it is hardly onerous.

Yet Shelby County, Ala., seeks the provision’s repeal, pronouncing itself cured of the attitudes that made it necessary. “The children of today’s Alabama are not racist and neither is their government,” wrote Alabama Attorney General Luther Strange in USA Today last week.

It was rather like hearing a wife beater say he has seen the error of his ways and will no longer smack the missus around. Though you’re glad and all, you still hope the wife’s testimony will carry a little more weight in deciding whether the restraining order should be lifted.

But the court’s conservatives seemed eager to believe, peppering the law’s defenders with skeptical questions. Indeed, Justice Antonin Scalia branded the law a “racial entitlement.”

Sit with that a moment. A law protecting the voting rights of a historically disenfranchised minority is a “racial entitlement?” Equality is a government program?

Lord, have mercy.

There is historical resonance here. In the 1870s, the South assured the federal government it could behave itself without oversight. The feds agreed to leave the region alone where race was concerned. The result: nearly a century of Jim Crow. Now here comes Shelby County, saying in effect: We’ve changed. Trust us.

It is an appeal that might have seemed persuasive back when I was young and naïve, sitting on Cathy’s lap (or she on mine) and thinking race was over.

But that was a long time ago.

Yes, the South has changed — largely because of the law Shelby County seeks to gut. Even so, attempts to dilute the black vote have hardly abated. We’ve just traded poll taxes and literacy tests for gerrymandering and Voter ID laws.

So we can ill afford to be as naïve as a top court conservative at the prospect of softening federal protection of African-American voting rights. “Trust us,” says the South. And the whole weight of history demands a simple question in response.